1. Field of the Invention
This invention relates to a check valve, an auxiliary circulating device such as a blood auxiliary circulating device which is typified by an auxiliary artificial heart utilizing the check valve, and to a method for driving the auxiliary circulating device.
2. Description of the Prior Art
Such various properties as durability, retention for blood circulation, blood compatibility (antithrombogenicity, antihemolysis), and histocompatibility are required for a check valve to be employed for an blood auxiliary circulating device such as an auxiliary artificial heart to support a dysfunctional heart. As of now, as the check valve are exemplified a mechanical valve such as a ball valve, a tilting disk valve and a two lobe valve.
At present, the two lobe valve is mainly employed as the check valve because the valve can make large central flow and large efficient valve opening area easily, and requires only small space in closing motion. With the two lobe valve, however, blood may be coagulated and accreted at the hinge of the disk of the valve.
In view of high durability and high degree of freedom of material selectivity, in contrast, it is desired to employ the ball valve as the check valve. With the ball valve, however, when spherical ball members are latched at latching members in the casing member of the valve, the ball members may be slipped away from the latching members by forward flow flux due to the insufficient latching. Therefore, blood can not be flowed stably, resulting in thromboembolism.
FIG. 1 is a schematic view showing a conventional ball valve. As shown in FIG. 1, when forward flux occurs, in the casing member 1, the spherical ball member 2 is moved upstream and latched at the latching members 3. In this case, the forward flux is flowed through the space around the ball member 2. However, the ball member 2 is slipped away from the latching member 3 due to the backward vortex flow for the upstream from the forward flux because the ball member 2 is made spherical. As a result, the forward flux may be blocked with the slipped ball member 2, resulting in the thromboembolism.